In many countries, exposing your shoulders or legs when visiting a holy place will offend the locals and get you barred from entry.
In Italy and Israel, women will need to cover their shoulders at religious sites, while men may be asked to cover their heads.
When visiting Buddhist temples in Asia, shorts or skirts should cover the knees. Same goes in Spain during holy days, such as Easter.
In Muslim countries, it is recommended that women wear loose-fitting clothing and cover their arms, legs and chest everywhere they travel.